From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D877C2BA1A for ; Tue, 7 Apr 2020 03:06:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BE35320BED for ; Tue, 7 Apr 2020 03:06:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="f2l4Qn28" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BE35320BED Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6AC908E0034; Mon, 6 Apr 2020 23:06:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 60DE48E0001; Mon, 6 Apr 2020 23:06:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 524298E0034; Mon, 6 Apr 2020 23:06:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0115.hostedemail.com [216.40.44.115]) by kanga.kvack.org (Postfix) with ESMTP id 34C488E0001 for ; Mon, 6 Apr 2020 23:06:23 -0400 (EDT) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id F20D8A8CE for ; Tue, 7 Apr 2020 03:06:22 +0000 (UTC) X-FDA: 76679570604.07.air87_71e4600a1b405 X-HE-Tag: air87_71e4600a1b405 X-Filterd-Recvd-Size: 4422 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Tue, 7 Apr 2020 03:06:22 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 16BA5215A4; Tue, 7 Apr 2020 03:06:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586228781; bh=3if5tnzyJFduFBNK/IGWueBdg407EpGBRGITCFcmPpM=; h=Date:From:To:Subject:In-Reply-To:From; b=f2l4Qn28NGw+KeX1cEsZ0T/imBCKApgaWq7MpJoJ/+fewGNxgCEoec2a2UOQsHGNj JrngQyoBKbIOHQqqzPLhAkO/60kWX85yHz+ZN0Ljzszgtd/ioKhazsGdGU7Ug+95aN 2533o13xabfvaRYb6Rz8rcyhp/36dqzuZyV/WfkQ= Date: Mon, 06 Apr 2020 20:06:20 -0700 From: Andrew Morton To: aarcange@redhat.com, akpm@linux-foundation.org, bgeffon@google.com, bobbypowers@gmail.com, cracauer@cons.org, david@redhat.com, dgilbert@redhat.com, dplotnikov@virtuozzo.com, gokhale2@llnl.gov, hannes@cmpxchg.org, hughd@google.com, jglisse@redhat.com, kirill@shutemov.name, linux-mm@kvack.org, mcfadden8@llnl.gov, mgorman@suse.de, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, peterx@redhat.com, riel@redhat.com, rppt@linux.vnet.ibm.com, shli@fb.com, torvalds@linux-foundation.org, xemul@openvz.org Subject: [patch 047/166] userfaultfd: wp: don't wake up when doing write protect Message-ID: <20200407030620.BboDfS25Q%akpm@linux-foundation.org> In-Reply-To: <20200406200254.a69ebd9e08c4074e41ddebaf@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Peter Xu Subject: userfaultfd: wp: don't wake up when doing write protect It does not make sense to try to wake up any waiting thread when we're write-protecting a memory region. Only wake up when resolving a write protected page fault. Link: http://lkml.kernel.org/r/20200220163112.11409-16-peterx@redhat.com Signed-off-by: Peter Xu Reviewed-by: Mike Rapoport Cc: Andrea Arcangeli Cc: Bobby Powers Cc: Brian Geffon Cc: David Hildenbrand Cc: Denis Plotnikov Cc: "Dr . David Alan Gilbert" Cc: Hugh Dickins Cc: Jerome Glisse Cc: Johannes Weiner Cc: "Kirill A . Shutemov" Cc: Martin Cracauer Cc: Marty McFadden Cc: Maya Gokhale Cc: Mel Gorman Cc: Mike Kravetz Cc: Pavel Emelyanov Cc: Rik van Riel Cc: Shaohua Li Signed-off-by: Andrew Morton --- fs/userfaultfd.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) --- a/fs/userfaultfd.c~userfaultfd-wp-dont-wake-up-when-doing-write-protect +++ a/fs/userfaultfd.c @@ -1812,6 +1812,7 @@ static int userfaultfd_writeprotect(stru struct uffdio_writeprotect uffdio_wp; struct uffdio_writeprotect __user *user_uffdio_wp; struct userfaultfd_wake_range range; + bool mode_wp, mode_dontwake; if (READ_ONCE(ctx->mmap_changing)) return -EAGAIN; @@ -1830,18 +1831,20 @@ static int userfaultfd_writeprotect(stru if (uffdio_wp.mode & ~(UFFDIO_WRITEPROTECT_MODE_DONTWAKE | UFFDIO_WRITEPROTECT_MODE_WP)) return -EINVAL; - if ((uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_WP) && - (uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_DONTWAKE)) + + mode_wp = uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_WP; + mode_dontwake = uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_DONTWAKE; + + if (mode_wp && mode_dontwake) return -EINVAL; ret = mwriteprotect_range(ctx->mm, uffdio_wp.range.start, - uffdio_wp.range.len, uffdio_wp.mode & - UFFDIO_WRITEPROTECT_MODE_WP, + uffdio_wp.range.len, mode_wp, &ctx->mmap_changing); if (ret) return ret; - if (!(uffdio_wp.mode & UFFDIO_WRITEPROTECT_MODE_DONTWAKE)) { + if (!mode_wp && !mode_dontwake) { range.start = uffdio_wp.range.start; range.len = uffdio_wp.range.len; wake_userfault(ctx, &range); _